At present, with the development of the optical technology, display devices are increasingly updated and developed. Most of light sources in display devices are light emitting diodes (LEDs) and laser sources. Laser sources have been widely applied to various apparatus, for example, laser projection displays or the like, due to their good monochromaticity, good directivity and high brightness.
However, in display devices, because of long-term impact from dust, temperature and other factors, the light sources, particularly laser sources, will have attenuation, leading to an offset in the color temperature of images and thus an offset in the white balance, and resulting in too bright displayed pictures or color derivation. Consequently, the quality of display of products is deteriorated.